/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.cloudera.util;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;

/**
 * This is similar to a ByteArrayInputStream but instead wraps a ByteBuffer
 */
public class ByteBufferInputStream extends InputStream {

  private final ByteBuffer buf;

  public ByteBufferInputStream(ByteBuffer buf) {
    this.buf = buf.asReadOnlyBuffer();
  }

  @Override
  public int read() throws IOException {
    try {
      return buf.get();
    } catch (BufferUnderflowException e) {
      throw new EOFException();
    }
  }

  @Override
  public int read(byte[] bytes, int off, int len) throws IOException {
    // Read only what's left
    len = Math.min(len, buf.remaining());
    try {
      buf.get(bytes, off, len);
    } catch (BufferUnderflowException e) {
      throw new EOFException();
    }
    return len;
  }

  @Override
  public int available() {
    return buf.remaining();
  }
}
